Pneumatic Flushing Valve is WRAS Approved and available in 6/4, 5/3 or 4/2.6 litre dual flush that converts into a 6 or 4-litre single flush option. 
 
Features
6/4 Litre Dual Flush and 6 Litre Single Flush
51mm [2"] Outlet
Fitted with a long Life Silicon Rubber Seal
Can be operated by a wide range of pushbuttons, push plates and electronic sensors (Sold seperately)